Raised levels of plasma big endothelin 1 in patients with colorectal cancer

Background The aim was to assess the role of plasma Big Endothelin (ET) 1 levels as a marker of disease presence and stage in colorectal adenocarcinoma. Methods Big ET‐1 was measured in the plasma of 37 patients with colorectal cancer. Preoperative systemic plasma levels of Big ET‐1 in patients with cancer were compared with levels in 20 age‐ and sex‐matched controls. Portal plasma samples were collected at operation in addition to peripheral venous samples. Immunohistochemical staining for Big ET‐1 was performed on a selection of primary tumour specimens and liver metastases. Results Median (range) preoperative systemic plasma levels of Big ET‐1 were significantly higher in patients with cancer than in controls (1·0 (0·3–9·7) versus 0·2 (0·0–6·0) fmol/ml; P = 0·0001). Intraoperative portal plasma levels of Big ET‐1 were significantly higher in patients with Dukes' ‘D’ disease than in patients with Dukes' A, B and C disease (2·1 (1·4–10·0) versus 1·2 (0·3–6·6) fmol/ml; P = 0·01). Similarly, systemic plasma levels were significantly higher in patients with Dukes' ‘D’ disease than in those with localized disease (1·9 (1·2–9·7) versus 1·2 (0·2–8·3) fmol/ml; P = 0·01). The presence of microvascular invasion in the tumour specimens was associated with a significantly raised portal plasma level of Big ET‐1 (1·6 (1·5–2·1) versus 1·1 (0·8–1·3) fmol/ml; P = 0·04). Immunohistochemistry localized Big ET‐1 to the cancer epithelial cells. Conclusion The plasma level of Big ET‐1 is significantly raised in patients with colorectal cancer. Patients with liver metastases have significantly higher levels than those with localized disease. © 2000 British Journal of Surgery Society Ltd